Case Report: Supercharged end-to-side anterior interosseous to ulnar motor nerve transfer for ulnar nerve neuropathy after cross pinning of pediatric supracondylar humerus fracture

Abstract

Ulnar nerve neuropathy following pediatric supracondylar humerus fracture fixation with cross pinning poses challenges in management. Despite various treatment strategies, including conservative approaches and early intervention, achieving complete neural recovery remains elusive in some cases. This paper presents a novel approach utilizing supercharged end-to-side anterior interosseous nerve transfer for a 13-year-old patient who experienced persistent ulnar neuropathy after K-wire removal. The patient underwent neurolysis of the ulnar nerve followed by nerve transfer, resulting in significant improvement in function and strength. This case highlights the potential efficacy of combining neurolysis and supercharge techniques in pediatric ulnar neuropathy cases refractory to conservative treatment, offering a promising avenue for enhancing patient outcomes.

Keywords: case report; pediatric; supercharged end-to-side nerve transfer; supracondylar distal humerus fracture; ulnar neuropathy.

Figure 1

(A) AP view of the fracture before percutaneous fixation with K-wires. (B) Lateral view. The images show a humeral supracondylar linear fracture, which could have been treated conservatively, but the patient received K-wire fixation at another hospital. (C) Left distal humerus supracondylar fracture, status post closed reduction and internal fixation with cross k-wires fixation. (D) Marked claw deformity of the 4th and 5th fingers. (E) Intrinsic muscle atrophy with weakness in thumb and finger adduction (positive Froment sign and Wartenberg sign).

Figure 2

(A,B, elbow). (A) Scars of previous k-wires fixation. (B) No notable adhesions, evident ruptures, or neuroma formations were found along the ulnar nerve pathway. However, slight scarring within nerve fascicles suspected to be caused by K-wire penetration was observed. (Above green patch) (C–E, Forearm). (C) AIN and the PQ muscle were exposed. (D) AIN was traced to the AIN- PQ muscle junction first, and further dissected distally by releasing the PQ muscle. (E) The motor component of the ulnar nerve, located between sensory component and the dorsal cutaneous branch of ulnar nerve, was further dissected. (F) AIN was transferred to the dorsal surface of ulnar nerve motor component. (White arrow). AIN, Anterior interosseous nerve; PQ, pronator quadratus; UN, ulnar nerve; DCB, dorsal cutaneous branch.

Figure 3

(A) After a six-month OPD follow-up, the 4th/5th finger claw deformity returned to normal. (B) No atrophy of intrinsic muscle or weakness in thumb and finger adduction.